Aluminum Castings

Make Your Aluminum Castings Look Great!

CastingsAlpha Metal Finishing Company offers finishing capabilities for aluminum castings. Aluminum castings require special care in dealing with the secondary alloys within the casting. Alpha has developed a proprietary process to handle your casting needs at no extra cost to you!

Cast aluminum parts in general will not anodize as well because of their tendency toward porosity. Pores do not anodize and contribute to the same type of problem that highly alloyed aluminum parts encounter. Good high-density castings without porosity will anodize with good results. It should be noted that in color anodized castings some difference in color will exist between machined surfaces and the natural as cast surfaces.

For a best overall cosmetic look, the better casting alloys are 514, 518, 520, 535, 713, and 771. If the aluminum casting has more than 12% silicon in the alloy or high amounts of copper we may not recommend anodizing. Higher purity aluminum, (less alloys), anodize better, producing better finishes. For more information on anodizing aluminum castings visit

For further expert research on the subject we recommend The Science of Successfully Anodizing Die Cast Substrates by Jude Mary Runge and Larry Chesterfield.

Understanding and Specifying Anodizing

Anodizing is perhaps the most common specified finish for aluminum components. We receive many questions from manufacturers related to how the process works. With the permission of Joseph Osborne we provide this excellent resource on understanding and specifying anodizing.